I have and use a P11 for carry purposes.
Couple of issues maybe: (I have not had them)
One would be an ammo problem with hard primers (what kind of ammo was it?).
Home gun smithing by previous owner to "lighten" the trigger by doing a "paper clip fix". Check out
www.ktog.org for more info on Kel-tecs.
I would ask the previous owner about the "lightening" the trigger issue.
The good news is Kel-tec has by far the best service team in the business for the first or 99th owner of the gun. Note: Florida where they are located prohibits a mfg in registering/keeping track of SN and names.
Let us know some more information and ask me any additional question. Note: The only issue I have had was feeding 147 square nose bullets. I hope this helps.